NAME:
       caldatm
 PURPOSE:
       Find year, month, day, hour, minute, second from Julian Date.
 CATEGORY:
       Astronomy
 CALLING SEQUENCE:
       caldatm, jd, y, m, d, hour, min, sec
 INPUTS:
       jd = Julian day number (like 2447000.5).   in
 KEYWORD PARAMETERS:
 OUTPUTS:
       y = year (like 1987).                      out
       m = month number (like 7).                 out
       d = day of month (like 23).                out
       hour = hour of day (like 12).              out
       min = minute of day (like 0).              out
       sec = second of day (liek 0.0).            out
 COMMON BLOCKS:
 NOTES:
  This routine is based on the formulas given in "Astronomical Formulae for
    Calculators," 2nd. ed., by Jean Meeus on pages 23-29.  This algorithm
    works for any date in either the Julian calendar (before 1582 October 4)
    or the Gregorian calendar except for negative Julian Day numbers.

 MODIFICATION HISTORY:
       M. Buie, 1991 Oct 10, Lowell Observatory
       DWL, August 6, 1993, Modifications to operate with vector input.